Corrosion Behavior of Electrodeposited ZnNi Alloy–CeO 2 Modified SiO 2 Particle Composite Coatings

In this research, CeO2 modified SiO2 powder was prepared for electrodepositing ZnNi alloy–CeO2 modified SiO2 particle composite coatings. Corrosion behavior of the ZnNi/(SiO2)CeO2 composite coatings was studied by the potentiodynamic polarization method and neutral salt spray test. The results show that the composite coating obtained at the plating current density of 3 A/dm2 in 20 min has the chemical composition with the nickel content of 14.90 wt %, which is composed only of the gamma phase. This composite coating has the brightest surface and the best corrosion resistance. The coating has the largest polarization resistance of 2430.48 Ω cm2 from polarization curve and the time for appearing the first red rust spot on the surface of this coating is the longest, lasting 1008 h.